26.Remove_Duplicates_from_Sorted_Array.py

# Given an integer array 'nums' sorted in non-decreasing order, remove the duplicates in-place such that each unique element
# appears only once. The relative order of the elements should be kept the same. Then return the nnumber of unique elements in 'nums'.

# Consider the number of unique elements of 'nums' to be 'k', to get accepted, you need to do the following things;

# Change the array 'nums' such that the first 'k' elements of 'nums' contain the unique elements in the order they were 
# present in 'nums' initially. The remaining elements of 'nums' are not important as well as the size of 'nums'.

# Return 'k'

# Example:1
#   Input : nums = [1, 1, 2]
#   Output: 2, nums = [1, 2, _]
#   Explanation: Your function should return k = 2, with the first two elements of nums being 1 and 2 respectively.
# It does not matter what you leave beyond the returned k (hence they are underscores).

# Example:2
#   Input : nums = [0, 0, 1, 1, 1, 2, 2, 3, 3, 4]
#   Output : 5, nums = [0, 1, 2, 3, 4,_,_,_,_,]
# It does not matter what you leave beyond the returned k (hence they are underscores).



# ----------Solution------------>

class Solution:
    def removeDuplicates(self, nums: List[int]) -> int:
        r = 1

        for i in range(1, len(nums)): #Start iterating from the second element (i = 1) to the end of the list.
            if nums[i-1] != nums[i]: #Compare the current element with the previous one 
                nums[r] = nums[i]
                r += 1
        return r